Decorative lamp



FIG. 1 is an isometric view of the decorative lamp showing my new design;

FIG. 2 is an elevation view of a first side thereof, being representative of all four symmetric quadrants;

FIG. 3 is an elevation view turned 45 degrees from the view illustrated in FIG. 2 thereof, being representative of all four symmetric quadrants;

FIG. 4 is a planar top view thereof; and,

FIG. 5 is a planar bottom view thereof.

The broken lines shown on the drawings depict portions of the lamp that form no part of the claimed design. 

CLAIM I claim the ornamental design for a decorative lamp, as shown and described. 